Astronomers Spot a New, Tiny Neighbor for Our Milky Way Galaxy
Our Milky Way galaxy may have a new neighbor. The Milky Way is part of a cluster of more than 50 galaxies that make up the "Local Group" but now, scientists have found a tiny and isolated dwarf galaxy nearby at just seven million light-years away.
The new galaxy, named KKs3, was discovered with the help of the Hubble Space Telescope. This galaxy is located in the southern sky in the direction of the constellation of Hydrus. It's so small that its stars actually have only one ten-thousandth of the mass of the Milky Way.
Kks3 is a dwarf spheroidal galaxy (dSph), lacking features like the spiral arms found in the Milky Way. These galaxy systems have an absence of the raw materials, such as gas and dust, that are needed for new generations of stars to form. This means that these galaxies are mostly composed of older and fainter stars. The raw material was probably stripped out by nearby massive galaxies like Andromeda.
Astronomers are particularly interested in dSph galaxies, since they may show them how different galaxies form in the universe. So far, though, only one other isolated spheroidal dwarf, called KKR 25, has been found in the Local Group.
"Finding objects like Kks3 is painstaking work, even with observatories like the Hubble Space Telescope," said Dimitry Makarov, one of the researchers, in a news release. "But with persistence, we're slowly building up a map of our local neighborhood, which turns out to be less empty than we thought. It may be that there are a huge number of dwarf spheroidal galaxies out there, something that would have profound consequences for our ideas about the evolution of the cosmos."
The findings reveal a bit more about these galaxies, and show that our Milky Way may have more company than expected. The scientists plan to continue to look for more dSph galaxies in the coming years.
The findings are published in the journal Monthly Notices of the Royal Astronomical Society.